a. Field of Invention
The invention is related to a method of homogenizing of melt, dielectric type, e.g. glass, by removing or minimizing local concentration differences, i.e. inhomogeneities in the melt, and an apparatus for performing of this method.
b. Description of Related Art
Traditional methods—insertion of gas-generating elements into the molten glass, when the gas bubbles are rising to the surface and thus mixing the content of the bath, are still being used for achieving homogenous melt, for example of glass.
Modern method of homogenizing is mechanical stirring by rotating stirrers. With regard to strictly laminar flow it causes only elongation of cords. The main disadvantage of mechanical rotation stirring is, that the stirrer action does not reach to the bottom, where the cords are located. It is not possible to lower the stirrer to the level of cords, i.e. 1 mm above the bottom.
Inhomogeneities of the melt, mainly in molten glass, are present mainly as cords, i.e. parts of melt in the shape of thin layers or cords of thickness 0.001-1 mm, that is in dimensions, which cause diffusion of visible light. Glassmelt with cords has different chemical composition and thus also different physical properties:                refractive index, then the cords are visible in the glass and visually disturbing, increasing diffusion of light and thus reduce spectral transmissivity, reduce brilliancy of the glass;        thermal expansion, which reduces strength of the product,        viscosity and surface tension, which have an influence on cord reduction through these properties having an adverse effect in the forming process;        and cords usually also have higher specific density. i.e. they are concentrated on the bottom and there, they create a thick cords, which are especially dangerous in final products.        
Description of microwave heating, in such manner that an inert additive chosen from the group of carbides, borides or nitrides is added to glass material mixture in the quantity 5 to 50 g to 1 kg of glass material, which is melted using microwave radiation of frequency 2450 MHz, is provided in Czech patents No. 289191 and No. 289193. The device consists of a microwave furnace with at least one generator. It is a modern method of glass material melting from cold conditions, i.e. of glass bath using microwave energy heating.
An additive agent—additive needs to be used for melting the glass.
The purpose of the present invention is homogenization of already melted glass, with a melt viscosity higher than that in the melting area, without the additive.